Midnight Moon
by heroherondaletotherescue
Summary: "Well, I'm coming. You can count me in," Black said. "What are you talking about, Black?" Rei asked with a huff, crossing her arms. "Your wedding of course. Remus will propose as soon as he discovers that it's you," Sirius said with a bark of laughter, looking over to James who too had a grin quirking at his lips. They were not going to let this go. / Marauders Era / Remus x OC


Midnight Moon

The full moon hung heavy in the midnight sky this evening in May. The bright circle in the sky and the disappearance of four members of the Gryffindor house-her friends to be specific-had been one of the first signs that something was wrong.

Rei had only stumbled upon this secret at the end of her fourth year at Hogwarts, and it had shocked her beyond belief, but somehow it had also made sense. The blurred waters had suddenly become clear and she was sure of what her role would be in this adventure.

It was only when she had moved into her fifth year that she actually began to do something about it. And by her sixth year she had perfected it. It had been a long and gruelling year of studying various potions and moving forward in her studies towards becoming a healer in an attempt to help her dear friend. It was only towards the end of her fifth year did she realise that Remus Lupin was more than a friend to her. He was someone that she loved, unconditionally, and the thought scared her beyond belief. But it didn't stop her from her quest.

Rei sat in the downstairs girl's lavatory that was mostly abandoned since the death of Moaning Myrtle years before she attended Hogwarts, brewing potions and healing balms that would ease pain and heal wounds. She then hunted around Hogsmeade for the finest of chocolates only to find that there wasn't anything _that_ great. So she made it her business to find some in her quaint hometown during the Christmas period. She was lucky enough to stumble upon a family owned vintage chocolatier that had all kinds of delicious desserts on their menu, only to find out that they didn't sell the chocolate that they used. But after a lot of bargaining and begging, she was able to get a few blocks for free for spending some time helping the old couple that owned the business sort through their finances and organise their paperwork. It had taken a long time but it had definitely been worth it. She had nearly a box full of authentic Swiss dark chocolate that was bitter to taste, but when it melted in your mouth it left a smooth decadent taste that had you wanting more. If she had to say so herself, it definitely had healing properties, and though she set some aside for Remus for his time of the month, she had done so for herself as well, not sharing it with any of her dorm mates when they had asked because it was just too good.

It was now nearing the middle of her sixth year at Hogwarts, and this marked the eighth month that she had been sending these care packages to the sandy blond she had eyes for, and she had patted herself on the back for keeping it a secret for so long. At first she had been afraid that Remus or any one of his friends would have found out, but they hadn't. Whether they were just that oblivious or perhaps turning a blind eye didn't matter, as long as they didn't call her out on it, she would continue doing it.

So she sat there on the floor of the room of requirement where she had stashed the monthly goods, preparing a small box covered in parchment, grumbling to herself about why she hadn't started sooner. It was the night of the full moon and usually she had placed the care package in his room at least a day before to avoid being caught by any of the marauders, or any other members of her house for that matter. It was tricky business but she always managed to get it done either with the help of a disillusionment charm or more recently, her transfigured form. Of course she would be a small tawny brown cat. She had worked on being able to become an animagi for months on end, and it was a lot of trial and error but she had got there in the end. At first it had been a dare from a friend of hers, who had soon told her not to go through with it once she saw that Rei was serious about it, knowing the dangers of being an unregistered animagi, but Rei had gone through with it, and it was the best thing she could have ever done for herself. It was exhilarating and it was certainly handy when you needed to get in or out of situations that you had very little control over. Her dearest friend Serena had felt guilty but she too was excited to see that Rei was able to do it in the end. Serena had been her friend since they were kids, both being muggle born and receiving letters to attend Hogwarts, the school of witchcraft and wizardry. It had been an amazing and rare event that both who had been childhood confidants were to receive invitations to the grand school due to the magical blood running through their veins.

The only person who knew about her little secret was Serena and for that she was grateful. She knew that Serena was one to keep quiet and would never spill the beans, so it gave her peace of mind that she had the support of her friend. But the nagging also came along with it. Serena had been trying for months to get Rei to confess to Remus, and on many occasions she had tried to set them up together, but Rei was far too shy to go through with it.

The clock chimed at the stroke of midnight, the sound shocking Rei from her concentration on tying up the package perfectly.

"Guess this is good enough," Rei said to herself, looking at the half bow that was formed. She had run out of the thin rope she had used to tie it together and figured it didn't really matter considering that Remus would open it soon after he returned from his escapades. She grabbed the checklist sitting on the desk next to her and went through it, making sure everything was in there.

 _Healing balm._

 _Draught of peace._

 _Swiss dark chocolate._

 _Spare bandages._

 _A small jar containing herbal tea leaves that are meant to sooth the soul (literally)._

Satisfied that she hadn't missed a thing, she pulled out her wand from her pocket and pointed it at the box.

"Diminuendo." The charm was instantaneous, shrinking the object to be the size of a sugar cube. She then took a step back, putting her wand back in its previous spot, holding the care package in one hand gently as she walked through the halls of Hogwarts at night, and back to her common room. She whispered the password to the fat lady in the portrait hole, ignoring the glare the old woman gave her, especially since she had been out and about at night, but she hadn't cared about it.

Rei entered the common room to feel the warmth of the fireplace crackling, but no one awake, giving her the perfect advantage to sneaking up to the marauders room. She carefully opened the door once clambering up the stairs to see the mess of a room it was. It was easy to spot Remus's bed, it was the one that was the tidiest and had the largest pile of books stacked on the side table, so much so that it was nearly toppling over. She smiled at the sight, especially when she recognised a few of the names, grinning at his choice of literature.

She then placed the package on the bed, and pulled her wand out once more, whispering the counter-charm.

"Engorgio."

The package returned to its original size after having been shrunk, and her job was done. It was then that she heard the creaking of footsteps and she panicked, not knowing where to flee.

"Shit," She cursed under her breath, looking around for a place to hide, wracking her brain for an idea. It was then at the bloody last second that she realised how stupid she was. In an instant, Rei was gone, and a small cat took her place, hiding behind the bed, the small head poking out to see who was walking up and into the room.

In came James Potter and Sirius Black tumbling into the room, with groans and moans of how it had been such a tiring night, Potter complaining in particular about how he had to run Quidditch practice in the morning bright and early.

Rei was happy that the two were so distracted and she was just about to make her escape when the door shut and her exit was gone. She let out a strangled meow sound, unable to help herself in this form and it was then that the two boys were alerted to the new addition to their room.

"Um Sirius, I know it's been a bloody long night, but is there really a cat in our room?" James asked, nudging his mate in the side from where he had been focused on pulling his shoes off. Sirius looked up and his eyes fell on the form of a little cat, one that he hadn't seen before in Gryffindor tower before. He blinked once and the cat was still there so he figured it was real.

"It's real," Sirius replied. "How the hell did it get up here? I didn't see it follow us in." Sirius frowned. His eyes then moved around the room, falling on Remus's bed where there was yet another one of those care packages. It definitely hadn't been there before they had left because Remus had been down in the dumps and complaining how it was too good to be true. Usually the mysterious box turned up a day before his transformation, but this month it had been missing. Suddenly, the gears began to turn in his head and he wondered if this cat was the one who brought it up.

"I might be insane throwing this out here, but what if that cat is the one?" Sirius asked on a whim.

"The one?" James asked in confusion, pushing his glasses further up the bridge of his nose until realisation hit him. " _Oh_ , you mean Remus's _one_?" James asked in clarification.

Sirius grinned when he noticed the cat's eyes widen suddenly and he knew this was no ordinary cat. It was giving him that same look that James gave him when he was transformed, the slightest cue or hint that they weren't truly animalistic beings.

"Of course."

" _Maybe_ ," James said, tilting his head and looking at the frightened cat. "Or it could be that someone in the tower left their door open and their cat ran wild and free?"

"Could be, but that box wasn't on the bed when we left a few hours ago. I don't know, it seems a bit suss."

"Well if this little cat is who you think it is, what can we do about it? It's not like we can force them out of their animagi form."

"Not with a spell perhaps but with our words," Sirius said. He walked over to his bed, stuck his hand under the mattress and pulled out the marauders map. He tapped his wand on the map and whispered the words softly, unlocking it, his eyes quickly darting to where he was standing now with James and the little cat in the room. "Rei Waters," Sirius read out on the map, unable to contain a grin.

"Oh my god, it's been you this entire time!" James exclaimed, nearly toppling over his own two feet in excitement. A burst of laughter came from Sirius throat and soon the two were cracking themselves up, going red in the face with laughter.

Rei was offended and let out what was meant to be perceived as a fierce cry but as a small cat they only found it adorable and began to calm down.

"You can turn back into yourself you know, you can trust us, _we are your friends_ ," James said. "We won't tell anyone."

Rei paused and then closed her eyes and the next thing she knew she was standing there dressed in her jeans and an autumn red woollen jumper, wand poking out of her pocket and her hair a bit of a mess. It was always the way after transforming.

"I can't believe it's you, man Remus is such a dolt, it's been you the entire time," Sirius said, awe in his voice. He had a new found respect for their quiet friend Rei Waters. He knew that she was a gem, and one of a kind, but this was something on an entirely new level.

"Promise me you won't tell him," Rei rushed in a panic, her heart racing with anxiety at the thought of Remus discovering it was her, and well, being disappointed. She knew that if anything were to happen between them it would have a long time ago. They were in the middle of their sixth year, with not long left to go at Hogwarts, and she figured if he had liked her, he would have approached her a long time ago.

James sensed her uncertainty and nodded, willing to keep quiet, but it was Sirius who was the one to object.

"And why not? It's been months of listening to him praise whoever sends these god damn care packages, and months of him complaining because he can't figure out who sent them," Sirius protested.

"That was the point you know. He wasn't mean to find out!"

"Why did you start sending them anyway?" James asked.

"Because," She said, this time in a softer voice. "He's my friend and when I found out what he goes through once a month I wanted to do something to help and this was my way of helping. He didn't want to tell me his secret but I found out anyway. I kept it a secret because he obviously wasn't ready for me to know and I didn't want to make things harder on him."

"Well, I'm coming. You can count me in," Black said.

"What are you talking about, Black?" She asked with a huff.

"Your wedding of course. Remus will propose as soon as he discovers that it's you," Sirius said with a bark of laughter, looking over to James who too had a grin quirking at his lips. But the other boy had more sense and noted that Rei's cheeks were bright red and that she was avoiding their eyes. James elbowed Sirius in the ribs getting him to tone it down a little, he felt bad for Rei. It reminded him of when he used to chase endlessly after Lily.

"Well, now that the cat's out of the bag," James began, being interrupted by Sirius.

" _Literally_."

"Why don't you want to tell Remus?" James asked.

" _Because it's embarrassing!_ What if he doesn't feel the same way? You don't just spend all this time and effort on someone who is just a friend, do you? It's just better this way," Rei said, crossing her arms defensively.

"I know exactly how you feel, that's how I felt with Lily, but look at us now, we're seeing each other and nothings felt more right," James said.

"I hate to agree with Prongs, but it's true," Sirius said. "You've been friends with us for years now, all of us know how Remus feels about you."

" _Yeah_ , as a friend."

"You're in denial."

"Look, it should be my choice and my choice is that no one tells him, so can you please do that? For me?" She pleaded.

"Well, if he finds out on his own then that's not our fault," Sirius said.

"Well he won't, if you don't tell him," Rei threw back.

"I'll make sure that Sirius does no such thing, but just think about it? Maybe?" James asked.

"Yeah, okay. I better go, it's late." Rei had already turned the handle of the door and was walking out the door when the two boys bid her goodnight, both of them happy that they had discovered the kindred spirit behind their friend's happiness and safety.

"Goodnight Rei."

"Night Rei."

"Night Black."

* * *

The following morning Rei woke up late for class, and she found herself falling out of bed, and rushing to get ready. Looking at her watch she knew that she had definitely missed breakfast in the great hall, but she had enough time to throw on her uniform and look slightly presentable so that was something.

Now running down through the common room and out of the portrait hole, she looked to her timetable to find out what classes she would be attending this morning. Elegantly scrawled on her piece of parchment were the times and class rooms. She groaned when she saw that she had double Herbology with Slytherin's at the end of the day, but she was happy to see that first thing she had Potions with Slughorn.

Rushing down the halls, and taking a short cut that she had discovered thanks to the ways of the marauders, she found herself at Slughorn's classroom in no time, slipping through the doors unnoticed and to an empty table towards the back of the classroom. It just happened to be right behind James and Sirius. She groaned audibly and banged her head on the table lightly, resting it there to give herself a moment to gather herself. James she knew wouldn't be a problem, but if Sirius was as pestering as he was last night, she was sure this would be a very long day.

"Waters, pleasure seeing you bright and early," Sirius greeted. "Long night?" He asked teasingly.

"Don't you know it," Rei bit back.

"Hullo," James said, in between chowing down on a piece of toast. He then passed one over that was in a napkin, jam atop and everything. "Thought you might like something after missing out on breakfast."

"You're an angel in disguise, James," Rei sighed, grabbing the toast and biting into it.

"Remus should be along soon, and Peter's got the day off. He took a nasty hit last night and broke a toe," Sirius joked. "So have you thought about how you're going to tell Remus yet?"

"I told you last night, I'm not telling him anything," Rei said, but it was hard to understand since she was still eating her on the go breakfast. She swallowed her food and was about to open her mouth once more to explain that she wasn't going to tell Remus that she was 1. Secretly sending him gifts once a month and 2. She was irrecoverably in love with him, but then he had to go and sit down next to her after silently entering the class room.

"Morning," Remus greeted with a soft voice, sleep evident throughout it. She looked over at him and sighed internally at the sight. Every single time their eyes met, her heart never failed to flutter, leaving her feeling weightless. She was completely and utterly _screwed_.

"Morning Remus," Rei replied shyly, ignoring the look of laughter written across Sirius's face as he watched the interaction, but then again James hadn't been any better and if it wasn't for the fact that he brought her breakfast this morning then she would have sent him the same glare she was currently directing at Black.

"So what were you talking about?" Remus asked.

Before anyone could say anything more, Professor Slughorn spoke, asking everyone to quiet down as the mornings lesson was about to begin.

"Today we will be brewing a draught of peace," Professor Slughorn announced. "Does anyone know what this potion does?"

Rei had raised her hand before anyone else, answering when the Professor nodded his head. "It's in the name Sir. A draught of peace relaxes ones anxieties or agitation. It essentially soothes the nerves of the drinker. But overdoing the ingredients can have a sedating effect and put the drinker into a deep sleep."

"Perfect answer! Ten points to Gryffindor."

Various Slytherin's in the room groaned audibly but Rei just rolled her eyes. Clearly no one had done the homework prescribed to them from their previous lesson.

"And can anyone name a few of the ingredients used in this potion?"

Once again the room was silent. "Did no one do the readings?" Professor Slughorn frowned, but it was soon removed when Rei faintly raised her hand once more. "Yes, Ms. Waters."

"Powdered moonstone, syrup of hellebore, powdered porcupine quills and powdered unicorn horn. Those are all of the ingredients used in the potion," She replied effortlessly, not even glancing at the textbook that was on her desk.

"Wonderful. And what might the colour be that this potion produces?"

"Turquoise blue," Remus answered, beating her to it. He smiled after he spoke, knowing very well the comforting colour of turquoise that brought him peace once a month.

"Correct, Mr Lupin. 5 points to Gryffindor."

Slughorn then went into more depth about the potion, as well as how careful and precise they had to be in the process that they brewed the draught. He was quick in instructing them on what pages the recipe was on and sent them off to work, partnering them up with the person they were sitting next too.

Remus smiled at Rei and she was sure that her heart was going to beat out of her chest if he looked at her like that any longer. She was glad to see that he had no additional obvious scars or injuries and hoped that last night hadn't been too hard on him. She wanted to tell him that she would do all the work, after all she had completed brewing this potion a dozen times, in fact she was sure she could do it with her eyes closed, but then that would give away that she knew his secret and she knew she couldn't do that.

They worked together in a comfortable silence and set to brewing the potion. Rei allowed Remus to cut most of the ingredients up as he carefully followed the recipe and she was in charge of adding them to the cauldron, stirring in the right direction and for exactly how long she needed. But whilst she was doing this she hadn't realised that Remus was watching her intently, noting that not once had she looked down at the recipe, her hands moving instinctively as she brewed it like she was making a fresh pot of tea, something she had done a hundred times over.

By the end of the lesson they had been one out of the three only groups in the class to accurately brew the potion, earning them extra points for their house, and getting them off writing an essay on it that was due tomorrow. Rei beamed at Remus with a smile at the end of the lesson and he returned it, but he could help but think that she was hiding something from him, and he was afraid that he knew exactly what it was.

Just as they were leaving the classroom and heading off to their next lesson for the day, Remus placed his arm on Rei's shoulder, catching her attention.

"Everything alright?" She asked.

"I was a bit lost in there today, I was hoping you might want to help me with some of the preparation for the next potions lesson?" Remus asked politely, and there was no way she could say no even if she was exhausted from the night before. But she figured if Remus could push on through the day after the night he had then she would be able to as well.

"Sure, how about we meet at the library after dinner?" Rei suggested.

"Sounds good. I'll see you later."

* * *

It was later that night and Rei found herself waiting in the library for Remus to show up. She had gotten a table towards the back of the grand library in a quiet corner, the warm yellow light from the lamps hanging above showering her with just enough light to see her work, but not so much that her eyes were starting to hurt.

She had laid out her work on the table including a few books that she thought might be helpful for next week's work. She dedicated a particular amount of time a week to practicing potions, knowing that if she began to lose her skill with it then it would cause problems for her. And eventually she actually found that she was enjoying herself. It was like baking, something she loved to do back home and a hobby that she had discovered with her mother when she was just a young girl, and it definitely got rid of those homesick feelings she had every now and then.

She was just getting drawn into her reading when a bag was placed down on the floor next to the desk she was occupying. She looked up to see it was Remus who looked a bit different than usual, he seemed like he was almost… nervous.

"Hey," She greeted with a smile.

"Hey."

"So, do you want to get started with the work?" Rei asked and Remus nodded, taking the seat next to her instead of the once across from her, taking her off guard. Not like she was complaining or anything, but he was sitting so close to her that she could smell his unique cologne mixed in with the earthy scent of the healing balm she gave him routinely every month, and knowing that he was actually using it and that it was helping warmed her heart.

"Do you might explaining this one?" Remus asked, pointing to a page in their textbook.

"Sure, so…," Rei began explaining the topic, making sure to avoid his eyes, knowing she would get lost in them if she looked directly at him. She felt her cheeks flush a little with the attention he was giving her, but it was delightful none the less. Remus seemed to grasp the concepts instantly and they then began answering the questions in silence until he spoke up.

"Rei," Remus spoke. "Can I, uh- can I ask you a question?" Remus was fiddling with the quill in his hands, his eyes watching her carefully.

"Yes," She replied, not looking up from her parchment where she was answering her final question.

"Why do you send me a box every month?" Remus asked. He was still unsure of himself, unsure if he had figured it out, but he as careful with how he questioned it. When Rei looked up at him with wide eyes, spluttering for a response, he had gotten his answer.

"I-uh, I don't know what you're talking about, Remus," Rei answered, fumbling with her words.

"I just want to know, what could make someone like you, someone with such a kind heart want to help a monster like me," Remus said in a low voice, almost like a whisper when he said the word Monster.

"That's the thing, Remus," Rei said, finding the courage to meet his eyes. "You aren't a monster. You're my friend, and I-I just wanted to help. That's why I sent those boxes. It was my way supporting you…" She looked down at her hands, unsure of what more to say, what more could be said. She didn't want Remus to be angry with her for keeping it a secret for so long.

"I-," Remus was unsure of what to say. His eyes were tearing up with emotion and he couldn't believe he had such a great friends. First the marauders, gallivanting with him every full moon, making sure that he didn't hurt himself or others, and now Rei, helping him heal his wounds. He didn't finish his sentence, instead, leaned over and hugged Rei tight, his arms resting behind her back, pulling her closer into his embrace. She had obviously been surprised as she let out a little squeak in shock before returning the hug. "Thank you."

"Anything for you, Remus. _Always_." Her hands curled up behind the back of his neck, resting just below his head. They stayed there, hugging each other for what felt like a long time before Remus pulled away. Rei was about to open her mouth to ask him a question, but her words were stolen by his lips as he pressed his mouth against hers, leaving her melting in his arms. Her eyes fluttered closed as her lips moved against his delightfully, eliciting a gasp from her mouth when he pulled back, giving her some room to breathe, but it only lasted a second as he titled his head, moving forward to capture her lips once more, leaving her breathless.

Their shared kisses had only lasted so long before Madame Pince had caught them, her voice bellowing throughout the back of the library, shocking them out of their heated embrace. Rei was sure she was blushing from head to toe and though Remus had pink cheeks as well, he had a dopey grin that was plastered on his face the entire time as he rushed to pack his bag, grabbing Rei's hand as they ran out the library as not to incur the wrath of Madame Pince any longer.

They ran all the way back to the Gryffindor common room, laughing their hearts away as they stumbled through the portrait hole, hand in hand, not even noticing that the room was empty and that it was nearing their curfew.

"I-I love you," Remus confessed, surprising Rei once more that night. He dumped their bags by one of the couches and took Rei into his arms. "I've loved you ever since fifth year when you threw that bat bogey hex at Sirius for swapping your pumpkin juice with a babbling beverage, and when I figured out that you had been taking care of me all this time, protecting my secret, I just fell deeper in love with you," Remus rushed out, finding that he was breathless after his confession. His hands were soft on her cheeks, and she was melting underneath his touch.

Rei felt like she was flying. Her heart was beating so fast she was sure it was going to burst. With a grin she leaned forward on her tippy toes, pressing a chaste kiss to Remus's lips, memorising the euphoric feeling of their lips against one another before pulling back and pecking his cheek.

"I love you too Remus," Rei said. "I loved you before I even knew what love was, and I loved you even more after I discovered your secret. You're one of the strongest people I know, and you have the kindest heart of all."

"Isn't that so sweet," Sirius cooed from above where he was on the staircase with James next to him.

"It is adorable isn't it?" James asked.

"Finally! That's all I have to say."

Rei blushed and buried her head in the crook of Remus's neck, trying to hide a smile when she heard him laugh, feeling the rumble of his chest beneath her.

"Oh stop it you two," Remus said, rolling his eyes. He looked down at Rei who was still in his arms and admired the sight, thinking that he could get used to this. When Rei didn't move from his arms, Sirius and James laughed louder and Remus gave them the finger, telling them to _Piss off_ , to which they did after yelling out congratulations.

"So, what do you say we go to Hogsmeade this weekend?" Remus asked.

"Well, I suppose it's an alright idea." Rei said, an amused sparkle in her eye.

"It's more than alright, it's perfect, just like you."

"Say something like that again and you're going to find yourself getting kissed," Rei said, feeling breathless whenever he spoke.

"Oh, I won't object."

Rei giggled and Remus's heart soared as she met him in the middle, for one last kiss goodnight. Though he had his troubles and his ailments, in the end, the universe had given him something to ease his pain, and he was never going to let go. Because for once in his life, the midnight moon had given him something back, and for that, he was grateful.

* * *

 **Authors Note:** Hi everyone! This is the first time I've ever written for Harry Potter and actually published it. I absolutely love the marauders era, and I was itching to write something. I know that all in all it might not be the most accurate, but it was something I had fun writing, and that's why I'm here. So I hope you can forgive me for any mistakes that I may have made or errors. But then again, this is fanfiction and not everything is going to be canon or exactly the same.

I hope you all enjoy it, please let me know what you liked and disliked, it's a journey of learning from here on. And to all of those interested in more, keep an eye out on my page, I have a few more one-shots up my sleeve!

 **Disclaimer:** _ **I do not own any of the characters/plot devices/content that have been taken from the world of Harry Potter. That all belongs to J.K. Rowling, and respectively, I only own my OC and creative genius.**_

Til Next Time!

\- Heroherondale


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